+#ifdef CONFIG_CRYPTO_DEV_HIFN_795X_RNG
+static int hifn_rng_data_present(struct hwrng *rng, int wait)
+{
+ struct hifn_device *dev = (struct hifn_device *)rng->priv;
+ s64 nsec;
+
+ nsec = ktime_to_ns(ktime_sub(ktime_get(), dev->rngtime));
+ nsec -= dev->rng_wait_time;
+ if (nsec <= 0)
+ return 1;
+ if (!wait)
+ return 0;
+ ndelay(nsec);
+ return 1;
+}
+
+static int hifn_rng_data_read(struct hwrng *rng, u32 *data)
+{
+ struct hifn_device *dev = (struct hifn_device *)rng->priv;
+
+ *data = hifn_read_1(dev, HIFN_1_RNG_DATA);
+ dev->rngtime = ktime_get();
+ return 4;
+}
+
+static int hifn_register_rng(struct hifn_device *dev)
+{
+ /*
+ * We must wait at least 256 Pk_clk cycles between two reads of the rng.
+ */
+ dev->rng_wait_time = DIV_ROUND_UP(NSEC_PER_SEC, dev->pk_clk_freq) *
+ 256;
+
+ dev->rng.name = dev->name;
+ dev->rng.data_present = hifn_rng_data_present,
+ dev->rng.data_read = hifn_rng_data_read,
+ dev->rng.priv = (unsigned long)dev;
+
+ return hwrng_register(&dev->rng);
+}
+
+static void hifn_unregister_rng(struct hifn_device *dev)
+{
+ hwrng_unregister(&dev->rng);
+}
+#else
+#define hifn_register_rng(dev) 0
+#define hifn_unregister_rng(dev)
+#endif
+